}

  @Override
  protected Map<String, Collection<Integer>> makePopulatedMap() {
    TreeMultimap<String, Integer> multimap = createMultimap();
    multimap.put("f", 1);
    multimap.put("f", 2);
    multimap.put("g", 3);
    multimap.put("h", 4);
    return multimap.asMap().subMap("e", "p");
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "a";
  }

  @Override

import com.google.common.collect.Multimap;

/**
 * Helper methods/assertions for use with {@code com.google.common.collect} types.
 *
 * @author Colin Decker
 */
@GwtCompatible
final class GoogleHelpers {

  private GoogleHelpers() {}

  static void assertEmpty(Multimap<?, ?> multimap) {
    if (!multimap.isEmpty()) {
      fail("Not true that " + multimap + " is empty");
    }
  }

  }

  @Override
  protected Map<String, Collection<Integer>> makePopulatedMap() {
    TreeMultimap<String, Integer> multimap = createMultimap();
    multimap.put("f", 1);
    multimap.put("f", 2);
    multimap.put("g", 3);
    multimap.put("h", 4);
    return multimap.asMap().subMap("e", "p");
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "a";
  }

  @Override

import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * A set multimap which forwards all its method calls to another set multimap. Subclasses should
 * override one or more methods to modify the behavior of the backing multimap as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

  public enum ListMultimapImpl {
    ArrayListMultimapImpl {
      @Override
      <K, V> ListMultimap<K, V> create(Multimap<K, V> contents) {
        return ArrayListMultimap.create(contents);
      }
    },
    LinkedListMultimapImpl {
      @Override
      <K, V> ListMultimap<K, V> create(Multimap<K, V> contents) {
        return LinkedListMultimap.create(contents);
      }
    },
    ImmutableListMultimapImpl {

import java.util.Map.Entry;
import org.jspecify.annotations.Nullable;

/**
 * An interface for all filtered multimap types.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
interface FilteredMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends Multimap<K, V> {
  Multimap<K, V> unfiltered();

  Predicate<? super Entry<K, V>> entryPredicate();

  }

  static <K extends @Nullable Object, V extends @Nullable Object> Multimap<K, V> multimap(
      Multimap<K, V> multimap, @Nullable Object mutex) {
    if (multimap instanceof SynchronizedMultimap || multimap instanceof BaseImmutableMultimap) {
      return multimap;
    }
    return new SynchronizedMultimap<>(multimap, mutex);
  }

import java.util.Comparator;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * A sorted set multimap which forwards all its method calls to another sorted set multimap.
 * Subclasses should override one or more methods to modify the behavior of the backing multimap as
 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

  }

  static <K extends @Nullable Object, V extends @Nullable Object> Multimap<K, V> multimap(
      Multimap<K, V> multimap, @Nullable Object mutex) {
    if (multimap instanceof SynchronizedMultimap || multimap instanceof BaseImmutableMultimap) {
      return multimap;
    }
    return new SynchronizedMultimap<>(multimap, mutex);
  }

 *
 * <h2>Collection types</h2>
 *
 * <dl>
 *   <dt>{@link Multimap}
 *   <dd>A new type, which is similar to {@link java.util.Map}, but may contain multiple entries
 *       with the same key. Some behaviors of {@link Multimap} are left unspecified and are provided
 *       only by the subtypes mentioned below.
 *   <dt>{@link ListMultimap}
 *   <dd>An extension of {@link Multimap} which permits duplicate entries, supports random access of